Abrasion resistance testing apparatus



Oct. 8, 1968 B. M. KAMERAS ABRASION RESISTANCE TESTING APPARATUS 3Sheets-Sheet 1 Filed June 18, 1965 aka BORIS M KAMERAS BY 4 0f 65 W IOct. 8, 1968 B. M. KAMERAS ABRASION RESISTANCE TESTING APPARATUS 3Sheets-Sheet 2 Filed June 18, 1965 ZNVENTOR BORIS M. KAMERAS BY W65 WOct; 8, 1968 B. M. KAMERAS 3,404,556

ABRASION RESISTANCE TESTING APPARATUS Filed June 18, 1965 3 Sheets-Sheet'5 I M T 8 /.9/ I89 x492 INVENTGR BORIS M. KAMERAS P: 2. E- E A RNEY3,404,556 'ABRASION RESISTANCE TESTING APPARATUS Boris M. Kameras,1'0715Clennnt Ave., Garrett Pa'rkrMd. 20766 "Filed June-18, 1965, Ser. No.464,942

. I 11 Claims. c1..7s 7

My invention relates to apparatus for testing the wear and abrasionresistance of surfaces comprising various materials to be tested,particularly the wear and abrasion resistance of coatings upon suchsurfaces. The material or coating is tested in the apparatus of thisinvention by directing a gas-propelled stream of abrasive particles incontrolled abrasive force against the surface for accurate measurementof the resistance of the surface thereto.

While it is old to measure the abrasion resistance of surfaces such ascoated or painted surfaces, as shown in US. Patent to Roberts et al.,No. 2,907,200, the present invention has several improved and novelfeatures.

One object of this invention is to provide an improved support means fora sample of the surface to be tested so that the test sample surface canbe accurately positioned with micro precision, with respect to a nozzlefrom which a test abrasive stream is emitted.

A further object is an improved mounting of a nozzle in conjunction witha lighting system for conducting a stream of gas-propelled abrasive withrespect to the test sample, so that the operator may visibly andaccurately set the position of zero clearance between the nozzle andtest sample.

A further object of the invention is to provide a means for setting theangle of the nozzle reproducibly with respect to a calibrated angularmeasuring device.

A further object is in the means for producing an abrasive feed tosuspend a constant quantity of abrasive in a jet stream so that the feedmay be of constant abrasive quality.

A further object is in the combination of the several means in a consolewith the several control means separated from the abrasive test chamber,with easy access to the test chamber and easy removal of spent abrasiveparticles in a manner to protect the functional elements.

The invention is further described in relation to the drawings in which:

FIG. 1 is a section in side elevation through the cabinet and some ofthe operating elements;

FIG. 2 is a longitudinal section through the nozzle assembly;

FIG. 3 is an enlarged detailed view through the test model adjustingmechanism including gear drive;

FIG. 4 is a side view of means for adjusting the drive shafting toeliminate backlash and misalignment;

FIG. 5 is an elevation in section taken on the lines 5-5 in FIG. 4;

FIG. 6 is a front elevation of a means for adjusting the angle of thenozzle;

FIG. 7 is a top plan view of the angle-adjusting means of FIG. 6;

FIG. 8 is a side elevation of the angle-adjusting means of FIGS. 6 and7; and

FIG. 9 illustrates an elevation section showing the feed and storagemeans for abrasive.

3,404,556 Patented Oct. 8, 1968 Referring first to FIG. 1, the devicecomprises an enclosed test chamber 10 mounted within an outer housing12. The housing 12 has several control elements for tests as willappear. The test elements comprise a table 14 on which is mounted a testsample, such as a painted plate of which the wear and abrasionresistance of the coating is to be tested by directing thereagainst acontrolled feed of abrasive suspended in a gaseous stream or jet. Thetest sample may be secured to the table surface with clamps, clips orthe like, but these are not generally needed.

The table 14 is supported on a shaft 16 (FIG. 3) slidably mounted withina sleeve 18 for vertical reciprocation upon a threaded stud 20 matingwith a threaded ring 22 on the lower end of the reciprocating shaft 16.In this construction, as the stud 20 is rotated in the threaded ring 22,the table supporting shaft 16 reciprocates slidingly within the sleeve18. The lower end 21 of the stud 20 is received in the bore 23 of asupporting base 24. The base 24 further supports an outer cylinder 26press fitted thereon at its edge 28. An intermediate ring 30, within thecylinder 26, supports the sleeve 18. The upper end of the cylinder 26may have a ring closure 32 and is fastened by studs 35 about a bore 34in the bottom wall 36 of the test chamber. A rubber sealing ring 38seals the bore 34 against the sleeve 18 to prevent passage of dust,particularly abrasive powder, into the adjusting gearing.

A lower bevel gear 40 is fastened about the shaft end 21 for rotarysupport on a boss 42 raised from the center of support 24. A matingbevel gear 44 is mounted horizontally to mesh with gear 40 and issupported in a sleeve bearing 46 in a side boss 48 extendinghorizontally from the cylinder 26. A horizontal shaft 50 is keyed to thegear 44 for rotation thereof. Thus, by rotation of shaft 50 and gear 44,gear 40 meshed therewith will drive stud 20 and effect verticalreciprocation of the shaft 16 and table 14 thereon.

An abrasive resistant bellows 52, formed of leather, plastic sheeting orthe like, has its upper end fastened to ring 54 by a spring, pressingthe bellows against press fitted ring 56 on the upper end of shaft 16.The lower end of the bellows 52 is fastened by spring ring 58 againstthe upper end of sleeve 18. The bellows 52 thereby serves to protect thesliding shaft 16, reciprocating within sleeve 18, against wear by dust,particularly abrasive dust, which might deposit upon the reciprocatingelements.

The horizontal shaft 50 has its outer end secured with in a sleeve 60(FIG. 5). Another .horizontal shaft 64 aligned with shaft 50 is fittedinto a contiguous hub member 62. Both hub members 62 and 60 supportresilient disc bodies 66 and 68 respectively which terminate in matingspoke elements 70 and 72 fastened together by rivets 74 so that disc 66and disc 68 are secured at their outer edges in a composite drive ofresilient discs, forming with each hub member 60 and 62 a continuousdisc drive radially fixed but axially resilient, thus resisting anyrotary play. In assembling, the shaft 50 is mounted in sleeve 60 withthe inner end bearing positively against the disc face 68 and set by setscrew 76. Similarly the shaft 64 is inserted in sleeve 62 and fixed by aset screw 78 so that the inner end bears positively against disc 66. Theassembly thereby forms a continuous drive through the shafts 64 and 50and gears 44 and 40 designed to mesh with each other and vertical stud20 without any play or backlash.

In a like manner, the opposite end of shaft 64 can be assembled with asecond disc-like drive 80 (FIG. 1) easily adjusted axially and similarlyproviding a firm rotary drive without any rotary play. The outer end ofshaft 64 terminates in a dial 82 which may have an indicator 84 at itsperiphery cooperating with lines of calibrations 86 on the face of thefront of the outer housing wall 12. The

calibrations 86 are suitably selected and spaced with respect to thesize of the gears, so that one calibration will result in a selectedvertical movement of table 14 through the bearing chain described tocause vertical reciprocation thereof through a fixed vertical dimension,for example, of an inch or some multiple thereof, to provide a fixedlinear dimension movement of the table 14 with a calibrated turn of thedial 82.

Other means for dial calibration than that described above may be used,For example, a multiple-turn potentiometer dial with more than onescale, or a dial of the direct read-out type, capable of calibration,may be substituted as known in the art of dial construction andcalibration.

The adjustment of .the shafting and 64 within the disc drive is set tosupport gears 44 and 40 in close driving mesh to remove all rotary aswell as axial play for exact transmission of a fixed verticaldimensional movement of table 14 with the rotation of the dial 82through a selected calibration. The lower end of the support base 24 asshown in FIG. 3 may have a threaded portion 88 which extends through thelower housing wall 12 and may be fastened thereto by a nut 90,preferably through an intermediate spacing washer 92 to secure the testtable assembly both to the test chamber floor 36 and housing 12 forfixed position operation to allow controlled vertical reciprocation ofthe table 14 within the test chamber with great precision by rotation ofdial 82.

As shown in FIGS. 1 and 2, a nozzle assembly 96 comprising a cylindricalhousing 98 is mounted inward from a bore in a rear wall 94 of the testchamber 10. The nozzle tip 100 is mounted over a swiveling core element102 to which it is threaded at one end 104, the inner core element 106comprising a ball bearing against a mating socket end 108 of a connectortube 110. The core 102 has slidingly fitted thereabout a sleeve 112whose inner end 114 receives and presses the ball 106 into the socket108. The end 114 has a shoulder which is engaged by an outer nozzlesleeve 116 whose inner end 118 is matingly threaded upon a nozzlehousing tube 120 A spacing washer 121 is fitted over the connector tubecentering the connector tube 110 within the sleeve 116, and engaging arounded end portion of the socket 108 so that tightening of the nozzlesleeve 116 secures the ball and socket joint under adjusted tensioncentered in supporting tube 120, so that the nozzle 100 is supportedtherein adjustably and securely to the tube 120. The connector tube 110has its inner end resiliently socketed with a flexible connector tube122 through which a suspended abrasive is carried from a source, as willappear. The connector tube 110 and core element 102 are bothconcentri-cally bored to provide a continuous duct with the hollowdownturned nozzle portion 101 at the end of the nizzle 100, as shown.According to the construction described, the ball jointed nozzlesupports the same in any adjusted resistance to movement so that thenozzle can be pre-set to angle with respect to the plate 114. The entirenozzle assembly as further described below can be rotated to anaccurately measured angle, hence in simple less flexible constructionsthe ball jointed nozzle mounting can be eliminated, if desired.

The tube is rotatably mounted in transparent spacing rings 124 coaxiallywithin the housing cylinder 98. The inner end of the tube 120 has fittedthereabout a Lucite or metallic bracket 126, keyed thereto at 128 forrotation therewith. The bracket 126 in turn has a narrow outwardlyextending sleeve 130. A Lucite crank member 132 (FIG. 6) is press fittedupon sleeve 130 so that as the Lucite crank element 132 is rotated withsleeve 130 and tube 120 as a pivot, the entire tube 120 and nozzle 100thereon rotate as a unit within transparent rings 124 as bearing supporttherefor.

- The Lucite crank member 132 is triangular in shape, like a sector of acircle pivoting about sleeve 130 and having an arcuate edge 140. Thecrank sector 132 bears parallel in rotation against a measuring plate134 which is fastened by studs 136 to the rear wall 94 of the testchamber. The measuring plate 134 has calibrations 138 extendingarcuately above the arcuate rim 140 of the crank member 132, as shown inFIG. 7. The rim 140 is calibrated on the arcuate edge 140 cooperativewith the calibrations 138 for adjusting the angular position of thecrank member 132 with respect thereto. The crank member 132 is slottedarcuately through an are 142 parallel to the arcuate edge 140. Theslotted arc 142 extends through the bod of the crank member 132 and iswide enough to slidingly receive, for unimpeded angular rotation, athreaded shank portion 144 of a stud having a knurled thumb screwfastened thereon and bearing against the surface of the crank plate 132for securing the same in any fixed and selected angular position withrespect to the measuring plate 134 as a 'detent. Thus, by suitablymounting the crank arm 132 upon the cylindrical shank 130, the entiresupport tube 122 and nozzle thereon may be rotated to a selected angleby positioning of calibrated positions 140 and 138 and fixed by thedetent; that is, fastening a thumb screw 150 in the selected arcuateposition. Thus, the nozzle 100 and downturned tip 101 may be rotated tothe desired angle with respect to the work table 14- and thus direct thejet of abrasive on a test sample at said selected angle. For calibrationand increased versatility, the angle measuring plate 134 may be furtherslotted at 135, and fastening stud elements such as thumb screws 136 asdescribed above for 150 may be used, so that the measuring plate itselfmay be arcuately moved in either direction, either for accuratepositioning of the indicia 138 thereon or for movement to angularposition more or less extended, thus providing more flexibility in themeasuring plate 134, as well as the crank member 132 cooperatingtherewith.

As indicated, the work table is accurately moved vertically in exactlymeasured calibrated units. It is desirable, however, in measuring thedistance of the work table and test sample from the nozzle, toaccurately pre-set both to a zero position. For this purpose, theposition of the test surface may be sighted by the test operator visiblywith respect to the nozzle tip, and any clearance therebetween may beobserved. In order to visibly see or examine that amount of clearance, asmall light bulb 152 (FIG. 2), connected to a current supply (notshown), is mounted from a bracket element 154 to project light throughthe space 156 between the nozzle support tube 120 and the tubularhousing 98. The light will not be intercepted 0r extinguished insubstantial luminosity because it will pass through the spacing rings124 since these for light trans missive purposes are formed of a lighttransmissive substance such as Lucite, glass, or the like. Consequently,the light rays will pass through the spacing rings 124 and illuminatethe nozzle tip 101, so that any clearance between said tip and the topof the test table 14 or workpiece thereon will be seen. For similarreasons, to avoid light interception at any given position of thenozzle, the crank member 132 and measuring plate 134 are also preferablyformed of light transmissive materials such as Lucite.

The duct 122, which may be abrasive resistant, formed of rubber, metalor armored construction, interconnects the nozzle 100 and a supply ofabrasive as shown in FIG. 9. In order to have available a substantialand relatively constant supply of abrasive powder, two supply hoppersare provided. A lower hopper 160 has a lower perforated plate 162 whichis mounted below a chamber 164 therein, so that the powder, byvibration, sifts continuously through the perforated tube into chamber180. The entire hopper 160 is supported upon the vibrating arm 166 of astandard electrical vibrator mechanism, which is not shown but is ofstandard construction, to impart continuous vibration to the chamber160. The supply of powder is picked up by a steady current of airentering through duct 168 from a supply of gas under pressure 170,

controlled by valves 172 and 174, standard for release of gas from abottled gas supply. The valve 172 may be preset manually and the actualgas flow may be controlled electrically by a solenoid valve 176 placedin the transfer duct 122 for remote control or adjustment thereof, as desired. Thus, the gas in controlled supply passes through inlet 168 andthence into chamber 180 beneath the vibrating grid 162 and picks up acontrolled amount of powder continuously sprinkled therein as asuspension and passes thence into duct 122 to the test nozzle.

The chamber 164 is preferably comparatively small, but is kept full tomaintain a constant weight and center of gravity so as to preserve theconstant amplitude of vibration essential for uniform abrasive flow. Inorder to maintain the quantity of powder in chamber 164 constant, amaster supply source comprising a hopper 182 mounted above the chamber164 is provided, which may also be filled with powder through an opening185 in the top 187 upon which :a manually depressible lid 189 is fittedand retained by a spring-loaded hinge 191 pressing the lid in tightclosure position against an O ring gasket 193, or to any desired leveland filled intermittently, that is, from time to time as the needappears. The large supply of powder from chamber 184 passes downwardthrough the opening or neck 186 of the hopper 182, and thence into thesmall supply hopper 160 connected thereto by way of a flexible tube 188.While, as shown in FIG. 9, hopper 182 is placed directly above hopper160, it is not necessary that these be mounted vertically aligned. Insome cases it would be preferred to mount hopper 182 displaced fromvertical alignment for the benefit of spacial arrangement within thecabinet, and sometimes for the benefit of reducing hydrostatic pressureupon the chamber 164. Such displacement is made possible by theinterconnecting flexible tube 188 which may be longer than shown toallow displacement to a gooseneck or other arrangement. The large hopper182 may be supported by a bracket 190 in any suitable manner. A pressureequalizing pipe 192 passes through the grid 162 and terminates in thechamber 180 so that an even supply of solids without bubbles, gas, orchannels is maintained in the chamber 164. By this construction anevenly flowing constant quantity of abrasive powder is available fromhopper 160 notwithstanding that hopper 160 is further supplied from thelarge source of hopper 182 which may have a wide-1y variable quantity ofabrasive. This serves to maintain a constant and even supply of abrasiveto the gas stream passing to the nozzle tip 101, even though the largehopper 182 may be filled intermittently from time to time as it mayappear to be necessary.

The supply device shown in FIG. 9 is mounted outside of the test chamber(FIG. 1) and principally within the cabinet 12 except for large gassupply, which may be a bottle of gas connected by a tube 168 placed moreremotely as a gas supply to the apparatus and replaced with a freshsupply bottle from time to time as needed. The other operatinginstruments, however, may be disposed within the chamber 12 as describedand moved portably therewith and controlled externally by dials mountedusually on the front wall of the housing.

The test chamber 10 contains only the movable table 14 and nozzle 100;their position and the complete testing operation may be fully viewedthrough a light transmissive front closure plate 194. The plate 194 maybe fitted against depressed supporting channels or strips as arectangular plate which may be lifted out and replaced, grasping a knobor handle member 196 for handling of the plate 194. By thisfconstrutcionall of the operating elements are disposed outside of the test chamberexcept the table and the nozzle. Thus all operating and control elementsare specially protected from extraneous wear by seepage of abrasivepowders into their operating joints. Also the table reciprocating meansitself is protected by the bellows 52 and the nozzle is enclosed in tube96 as described.

The test chamber 10 is maintained essentially free of spent dust byinserting the suction end of a vacuum cleaning tube into an aperture 198in an end wall 200 of the test chamber, thereby applying gaseous suctionthereto by the suction of an ordinary vacuum cleaner. In order tocomplement that suction and help sweep the spent abrasive dust from thechamber, a series of inlet holes 202 are bored in an opposite side wall204 of the test chamber through which a stream of scavenging air canenter. Thus, for cleaning of the chamber the suction tube of a vacuumcleaner applied through a duct 198 allows a stream of gas to enterthrough holes 200 near the bottom wall 36 of the test chamber, entrainthe spent abrasive dust therein, and be emitted under suction throughduct 198.

The device further provides two access openings for mounting and removalof test samples upon the test table 14 by removal of the transparentenclosure 194, which is fitted in its supporting brackets lyingangularly as shown, and which will be dust-tight to prevent abrasiveemission during use of the apparatus. For further manipulation, a secondopening is closed by a covering element 206 which covers the top of thetest chamber 10, and is lifted by a knob 208 for vertical access.

The outer housing itself may have a :hinged cover 210 which may beraised by grasping a knob 212, so that the cover can be swung verticallyopen upon hinges 214 in the back wall 12 of the assembly. A lightelement 216 can be mounted across the top of the chamber; preferably anelongated fluorescent tube light is mounted across the top of thecabinet for even lighting of the interior for further observation of thetest.

As thus described, an abrasive jet tester for testing the wearresistance of surfaces, particularly coated surfaces, is provided,including, an accurately positioned remote controlled test table, anozzle whose angle is easily set and maintained, and a zeroing light forsetting the nozzle and the sample at zero position. Close control isprovided for even distribution and constant supply of abrasive powder tothe gas stream. A test chamber is provided easily accessible through atransparent window to observe the results of the test.

The unit is provided with a timing means as known in the art formeasuring the duration of the test. Several elements as describedprovide greatly increased accuracy and convenience for testing theabrasion resistance of surfaces. More tests can be applied by the devicewith far greater precision and convenience.

Certain modifications may occur to those skilled in the art and,accordingly, it is intended that the description be regarded asillustrative and not limiting except as provided in the claims appendedhereto.

I claim:

1. In an apparatus for measuring wear and abrasion resistance to teststrength to applied abrasive particles, a housing having test controlmeans therein, partitioning elements disposed in said housing enclosinga test chamber, said partitioning elements supporting and separatingportions of said test control means with operating elements thereofextending through said partitioning elements from said housing into saidtest chamber for performing tests therein, exhaust means extending intosaid test chamber for withdrawing gases therefrom, partitioning elementsopposite to said exhaust means in said test chamber having at least oneopening near the bottom allowing ingress of air and providing thereby apurging stream of gas flowing from said opening across the bottom ofsaid test chamber entraining deposited abrasive particles for withdrawalas a stream through said exhaust means, and a removable transparentclosure exposing the test elements in said test chamber to externalobservation while applying external manual control of tests conducted insaid test chamber, said closure further providing external access tosaid test chamber to mount samples for performing surface wear andabrasion tests thereon.

2. The device as defined in claim 1 wherein control elements extendinginto said test chamber are protectively encased to resist ingress ofabrasive particles.

3. Device as defined in claim 1 wherein the test control means extendinginto said test chamber includes a nozzle conectcd to a supply ofabrasive particles and a carrier gas, said nozzle being supported insaid test chamber while emitting a gaseous jet of abrasive particles, atable for supporting the test sample below said nozzle, and meansoutside of the apparatus for accurately and measurably positioning saidtable and test sample with respect to said nozzle.

4. The device as defined in claim 3 wherein said nozzle has a downturnedtip from which the jet of gas having abrasive particles suspendedtherein is emitted, said nozzle being horizontally supported in saidtest chamber within a sighting tube extending through a partitioningelement, said sighting tube having at least one transparent closure, andilluminating means mounted in said housing positioned behind saidsighting tube and providing a beam of light illuminating said nozzle tipthrough said transparent closure, whereby the position of said nozzletip with respect to said test sample and table is illuminated forobservation of zero clearance.

5. In apparatus for measuring wear and abrasion resistance, a housing, ahorizontal test table for support of a test sample thereon, a nozzlesupported above said table, said nozzle being connected to a source ofabrasive and carrier gas therefor for emission as an abrasive jet fromsaid nozzle, said table being mounted upon a reciprocating support forvertical reciprocation, a dial control mounted outside of said housingcalibrated with indicia measuring the vertical positioning of said tablewith respect to said nozzle in micronic distances per digital reading,said dial and table being interconnected by shafting and adjustablenon-backlash gearing to raise and lower said table by movement of saiddial control.

6. The device as defined in claim 5 wherein the reciprocating supportbeneath said table is encased in a resilient vertical expandable bootprotective of the raising and lowering means for said table from damageby abrasive dust.

7. In apparatus for measuring wear and abrasion resistance, a housing, atest chamber within said housing, a horizontal test table for support ofa test sample thereon in said test chamber, means external of saidhousing for adjusting the vertical position of the test table, ahorizontal nozzle extending into said test chamber and having adownturned tip directing a jet of suspended abrasive in a carrier fluidupon said table and test sample thereon, a light mounted behind saidnozzle illuminating said tip and test table whereby the zero position ofsaid table is visibly adjustable externally of said housing with respectto the said nozzle tip.

8. Apparatus for measuring wear and abrasion resistance, comprising ahousing, a test chamber in said housing, a test sample supporting tablemounted for vertical reciprocation in said test chamber, means outsideof said housing for adjusting the vertical position of said table, ahorizontally mounted nozzle in said test chamber having a downturned tipfor projecting an abrasive jet upon a test sample mounted on said table,said nozzle being mounted for rotation of its tip to direct an abrasivestream at a selected angle upon the test sample, and means in saidhousing outside of said test chamber for pre-setting the angle of saidnozzle.

9. Device as defined in claim 8 wherein the nozzle is mounted forrotation in a tubular member supported from the wall of said testchamber, said tubular member having a radius larger than the length ofsaid downturned nozzle tip, a light conductive panel member fittedwithin said tubular member, a source of illumination behind said tubularmember whereby to illuminate said nozzle tip for visibly adjusting thedistance separating said nozzle tip and table and test sample thereon.

10. Apparatus for measuring wear and abrasion resistance comprising ahousing, a test chamber in said housing, a horizontally supported nozzleconnected to a tube at its inner end and said tube extending through awall of said test chamber and into said housing, a crank member securedto said inner nozzle end adapted to rotate said nozzle in angularmovement thereof, said crank member being planar body shaped as a sectorof a circle secured to said nozzle at the center and having a groovearcuately cut therein parallel to its arcuate periphery, and a detentextending through said groove having a fastener thereon adapted tosecure said sector crank element in a preelected fixed angular positionof said nozzle with respect to indicia disposed near the arcuateperiphery of said crank member, said indicia calibrated for measuringthe angular position of said crank and nozzle.

11. The device as defined in claim 4 including a source of carrier gasfor said feed of abrasive, a pair of supply hoppers mounted in avertical tier, one above the other, and interconnected by resilient ductmeans, means for vibrating said lower supply hopper and chamber belowsaid lower supply hopper into which abrasive particles are sprinkled byvibration of said hopper, said source of gas having duct means leadingto said chamber into which abrasive is vibrationally sprinkled and fromsaid chamber to said nozzle for conveying a constant supply of abrasivesuspended in said gas to said nozzle.

References Cited UNITED STATES PATENTS 2,299,405 10/1942 Prange 51-82,584,647 2/1952 Webber 518 2,799,155 7/1957 Newton et al. 73-72,907,200 10/1959 Roberts et al. 737 3,065,627 11/1962 Ross 73--73,229,498 1/1966 Oakes 73-7 3,307,296 3/1967 Ashworth 51-8 DAVIDSCHONBERG, Primary Examiner.

JEFFREY NOLTON, Assistant Examiner.

